Semiautomatic rifle



April 24, 1951 E. D. MARTIN ET AL SEMIAUTOMATIC RIFLE 3 Sheets-Sheet 1Filed April 30, 1948 JNVENTORS 06341? D; MARTIN 6- BY @50H65 E. MARTINTTRNEVS PR 24, 195 E. D. MARTIN ET Al. 2,5502@ SEMIAUTOMATIC RIFLE FiledApril 30, 1948 3 Sheets-Sheet 2 f7 49 f4 55 l N VEN TORS 1 50a/.w 0.MART/1v @0,965 f. MART/N Anfon/Mns pli 24, 1951 E. D. MARTIN ET ALSEMIAUTQMATIC RIFLE 5 Sheets-Sheet 5 Filed April 50, 1948 Patented Apr.24, 1951 UNITED STATES SEMIAUTOMATIC RIFLE Edgar D. Martin and George E.Martin, Corning, Ohio Application April 3o, 1948, seri-amp. 24,304

6 Claims. 1

This invention relates to firearms and more particularly to that classof firearms wherein the recoil .force is employed to eject an expendedcartridge and to perform additional functions whereby operation of thefirearm kis semi-automatic.

A main object of the invention is to provide a novel and improvedYfirearm of the semi-automatic type which is very safe to handle, sturdyin construction, Vand not subject to jamming.

A furtherbbject of the invention is to provide an improvedsemi-automatic firearm wherein a succession of cartridges may be firedwithout requiring the retraction of the bolt for each cartride, the boltbeing automatically moved rearwardly after the ring of a cartridge byrecoil action, the rearm including safety means for preventingaccidental firing thereof, and being very reliable in operation.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

Figure 1 is a longitudinal vertical cross-sectional view taken throughthe breech portion of a semi-automatic rifle constructed in accordancewith the present invention, the rifle being shown in a cocked position.

Figure 2 is a view similar to Figure 1 but showing the rifle parts infiring positions, the locking means for the cartridge clip being shownin a released position.

Figure 3 is a longitudinal horizontal cross-sectional -view ,takenthrough the breech portion of the rifle of Figure 1.

Figure 4 is a vertical transverse cross-sectional view taken on line 4-4of Figure 1.

Figure 5 is a vertical transverse cross-sectional view taken on line 5-5of Figure 1.

Figure 6 is a vertical cross-sectional view taken on line 3 6 of Figurel.

Figure 7 is a vertical cross-sectional View taken on line 1 1 of Figure1.

Figure 8 is a fragmentary side elevational 'view of the rifle of Figure1.

Figure 9 ris a transverse cross-sectional detail View taken through thebolt ofthe rifle of Figure 1 on line 3 9 of Figure 10.

Figure 10 is an enlarged perspective detail view of the bolt of therifle of Figure 1.

Figure 11 is an enlarged fragmentary detail horizontal cross-sectionalview taken through the receiver of the r'iiie of Figure 1 adjacent theforward end of the bolt, showing how an expend- 2 ed cartridge isejected from the rifle by reeoil action.

Referring to the drawings, Il designates the barrel of the rifle, theYrifle -s'toc'k being shown at I2. Designated at I3 is the receiver, therear end of barrel II being threaded into the forward endvof thereceiver. Rigidly secured to and depending from the forward portion ofreceiver I2 is the magazine housing I4 and likewise rigidly secured toand depending from the rear portion of receiver I2 is the sear andtrigger housing I5. The stock I2 is suitably recessed at IB to receivethe depending housings I4 and `I5. Housing l5 is formed with a bottomtransverse bar element I1. Secured to bar element by a machine screw I8is the forward end of the trigger guard I9. The rear end of said triggerguard is secured to the underside of stock I2 by a screw 20. Themagazine housing I'II is secured t0 stock I2 by suitable `fasteningmeans, not shown.

Pivotally secured on pin 21 in the .forward portion of sear housing I5is the sear block 22, said block being biased downwardly by a spring 23acting upwardly on a pin member 24 bearing on the bottom of receiver I3.Designated at 25 is the sear plate, said plate being formed with a slot26 engaging the transverse pin 21'. Designated at 28 is the sear springwhich bears between pin 2I and the sear plate 25, biasing said searplate rearwardly and upwardly with respect to pin 21.v The top portion28 of sear plate 215 projects througha slot 30 formed in receiver I3.The top portion 2971s forwardly` and downwardly inclined yand terminatesat its forward end in a lugY 3I adapted to overlie the top lofnsearblock 22 when the rifle is in a cocked condition, as shown in Figure I.The body portion `of scar plate 25 is received in a vertical slot 32formed in sear block 22.

The rear portion of sear block 22 is formed with a recess 33 in which isrotatably received the rounded end 34 of trigger arm 35. The trigger isgenerally designated at 35 and is pivoted to the side walls of housingI5 by a transverse pin 36. Trigger 35' is provided with a dependingfinger-actuated arm 31. When arm 31 is pulled rearwardly, sear block 22is rotated downwardly around pin 2| by trigger arm 35. Pin 21 then actson Sear plate 25 to move the rear end of the top portion 23 of said searplate downwardly. If thereafter there vis 'no restraint on said rear endof top portion 29, spring 28 moves sea'r plate rearwardly and' alsorotates it upwardly with respect to pin 21, whereby lug 3i is moveddown- 3 wardly into slot 32 into abutment with the front Wall of saidslot, as shown in Figure 2.

Designated at 38 is a safety catch which is rotatably mounted on a pin39 secured between the side walls of housing I5, the catch having aspring pressed ball 38 mounted in the lower end thereof and which ismovable into and out of seating engagementfin a groove 38" formed in thebottom bar element I1 of the housing I5 upon rotation of the catch 38toward and away from the sear block 22. formed with a notch 40engageable with the rear end of sear block 22 when said catch is rotatedfrom the full line position of Figure 1 to its dotted line position withthe spring pressed ball 38 seating in the groove 38 in the bottom barelement I1 of the housing I5, whereby block 22 is locked againstdownward rotation around pin 2|. Catch 38 is provided with a laterallyoffset upwardly extending actuating arm 4I terminating in a knurledfinger plate 42 positioned adjacent the rear portion of receiver I3.Block 22 is locked by moving plate 42 forwardly from the position shownin Figure 3.

Designated at 43 is a plug member which is threaded into the rear end ofreceiver I3. Plug member 43 is formed with an axial forwardly eX-tending reduced sleeve element44 and encircling said sleeve element is astrong coiled spring 45.

Surrounding spring 45 and longitudinally slidable1 in receiver I3 is agenerally cylindrical hammer member 48 whose bore is reduced at 41 todefine an internal annular'shoulder against which the forward end ofspring 45 bears. The outer surface of hammer member 45 is flattened atits bottom forward portion as shown at 48, the shoulder at the rear endof said flattened portion being engageable by the rear end of sear platetop portion '29 to hold hammer member 45 in a cocked position, as shownin Figure l, against the force of spring 45.

Designated at 49 is a bolt member slidably positioned in the forwardportion of receiver I3. Bolt member 49 is generally cylindrical inexternal contour, as shown in Figures 9 and 10, and is formed with anintermediate transverse slot 50. Extending through said slot 58 andprojecting throughja'longitudinal slot 5I formed in the side wall ofreceiver I3 is a finger bar 52 for manually retracting the bolt 49. Bolt49 is Safety catch 38 is y groove portion 59 when hammer 45 is in thecocked position shown in Figure 1.

Receiver I3 is formed adjacent its forward end with a longitudinal slot62 in its side wall and with an internal rib S3 opposite slot 52. Rib 63is formed with a forwardly facing shoulder 64, the shoulder 64 beingadapted to engage the rim 65 of a cartridge case 55 when said cartridgecase is driven rearwardly by recoil action when the rifle is fired. Asshown in Figure 11, the cartridge case 65 is rotated, by impact withshoulder 64, and is kicked out of the receiver I3 through the slot 62.Bolt 49 is formed with a keyway 31 slidably receiving the rib 63.Pivotally secured in the bolt 49 opposite said keyway is a forwardlyextending hook member B8 biased counter-clockwise, as viewed in Figure3, by a spring 69 positioned in a recess provided therefor in bolt 49and bearing outwardly on the rear portion of hook member 68. The hookedend of member is engaged over the rim 65 of the cartridge case itthrough slot 62, as illustrated in Figure 11.

Designated at 18 is a cartridge clip which is i received in magazinehousing I4 and contains a plurality of vertically stacked cartridgesbiased upwardly by a follower plate 1I and a follower spring 12'actingbetween plate 1I and the bottom;

formed with alongitudinal'axial bore 53 at its rear portion in which isslidably positioned a headed pin 54, and encircling the shank of saidpin is a spring which extends into sleeve 44r and bears on the end wallof said sleeve at its rear end and on the head of pin 54 at its forwardend. Bar 52 is formed with a recess 55 which receives the head of pin54, thereby locking bar 52 to bolt 49. Spring 55 exerts a forwardbiasing pressure on said bolt through theV The forward end of the groovein which firing pin 51 is Vsupported on bolt 49 is increased `in depth,as shownat 59. The forward end of firing pin 51 is formed with anenlarged head 6| adapted to engage the shoulder .at the deepened wall ofclip 10. formed with an opening 13 and receivable therein is a lug 14carried by a clip locking member 15. Member 15 is pivoted between thewalls of magazine housing I4 at 16 and is biased toward a lock- The rearwall of the clip 10 is'V formed in member 15.

Spring 11 biases mem-4 ber 15 in a counter-clockwise direction, asviewed in Figure 1, whereby lug 14 is normally main The clipy tained inthe opening 13 of a clip 18.

may be unlocked by manually rotating member 15 clockwise by means of adepending handle 18'` carried by said member to the position shown in 'iFigure 2. This is done whenever a clip is erilpty and is to be replacedby a new clip.

The forward end portion of bolt 49 is'` formed with a dependinglongitudinal rib 19 which normally loverlies the top cartridge in clip10, as When the rifle is shown in Figures 1 and 2. fired, the recoilmoves bolt 49Arearwardly to eject the empty cartridge case, as abovedescribed and allows spring 12r to move the stacked'cartridges upwardlyso that the top cartridgevin the stack moves into the positionformerly'o'ccupied by the ejected cartridge case immediately prior toits ejection from receiver I3. When the bolt 49 is returned by spring 55to the position ofA Figure 1, bolt 49 pushes the top cartridge intofiring position in barrel II.

In operating the rifle, the safety catch 38 is rst moved to the releasedposition shown in full line view in Figure 1. Finger bar 52 is thenpulled back as far as it will go. the upper rear end of sear plate25:withthe This interlocks rear shoulder defined by flattened portion48of hammer member 48, latching the hammer meme ber in cocked position.

As bar member 52 isf.,A

released, spring 55 moves bolt 49 forwardly and .v bolt 49 moves the topcartridgek in clip 18 vinto firing position in barrel I I, as shown inFigure l'. Since the hammer spring 45 is relatively strong as comparedto the sear spring 28, the lug 3| is held in overlying relation to thetop of Sear'.l

block 22. The rifle may now be red by pulling on trigger arm 31, wherebysear plate 25 is pivascensori. i

oted downwardly as. above l described, releasing the hammer 48and'causingithe firing pin-51 to detonate--r-the cartridge by the'impactof its head1'.

evemifi trigger :arml .is held 'ini-itsfrearwardly; pulled: 'ipositionlAscabove described,` the qrecoili. movement .zofirbolt.d9 and. thaemptycartridge,` caseel causes=..said...cartridge caserta; be eicetedr byrearwardsimpactwith..shouldereGL and as..

spring 55 returnsabolt .49. forwardly, a fresh cartridge is moved bysaid bolt'into firing position in barrelw! t.

again.

The renewed interlock. of sear plate top portion 29 with the hammer 46returns the forward top lug 3l of the sear plate from the position ofFigure 2, to the position of Figure 1 wherein it overlies the topsurface of sear block 22.

When the rie is loaded and cocked, if safety catch 38 is in its lockedposition, shown in dotted view in Figure 1, it is impossible'to fire therifle accidentally, inasmuch as both ends of the sear plate top portionabut the top surface of sear block 22, and said searblock is lockedagainstv rotation.

The isolation of hammer spring A5 from the bolt return spring 55 bysleeve member 44 makes jamming of said springs impossible.

While a specific embodiment of a rearm of the semi-automatic type hasbeen disclosed in the foregoing description, it will be understood thatvarious modifications within the spirit of the invention may occur tothose skilled in the art. Therefore it is intended that no limitationsbe placed on the invention except as defined by the scope of theappended claims.

What is claimed is:

1. In a firearm of the character described, a receiver, a hammer memberslidably mounted in said receiver, means biasing said hammer memberforwardly, a forwardly facing shoulder carried on said hammer member, asear housing secured to and depending from said receiver, a sear blockpivotally mounted in said housing for rotation in a longitudinal plane,a trigger pivoted in said housing and interengaged with said searVblock, a sear plate slidably and pivotally secured to said sear block,and spring means acting between said sear plate and sear block biasingsaid sear plate rearwardly and upwardly with respect to said sear block,the rear end of said sear plate being engageable with said shoulder.

2. In a firearm of the character described, a receiver, a hammer memberslidably mounted in said receiver, means biasing said hammer memberforwardly, a forwardly-facing shoulder carried on said hammer member, asear block pivotally secured to said receiver, and a sear plate slidablyand pivotally secured to said sear block and engageable with saidshoulder.

3. In a firearm, a receiver, a hammer disposed within said receiver andslidably supported. in the latter for movement from a cocked positioninto a firing position, spring means operatively connected to saidhammer for biasing the latter into said firing position, a sear blockmounted on said receiver for pivotal movement about a transverse axistoward and away from said receiver, a sear plate disposed contiguous tosaid sear block and The rifle is nowaready to be iii-edf..T

mounted-i onf. the flatter'. fores1idingrmovexnent-. longitudinally ftnereofvand forlpivotal movementv aboutea second*transverse:.axisspacedfromai first transverseiaxis,1saidfseaiimlaite.hailing :iSg-z uppei-endextending-through; said receiver and engageable :with: said hammereina,:select;p0Sition; of its sliding.and:-rotary movementfforlocking.;Vsaid .hammer .invsaidlcocked .positiomgand trigger f means` operativelyconnected tofsaidf-lseal :blockl:

for rotating theslatterabout saidfirst:transverse;

axis and foresimultaneously'.efectinff :thefsliding;4

and pivotal movement .of-.ssaid :searplategout 'of said select position:

4. In\aY-firearmg@ar-receiver, a hammer disposed within said receiverand slidablysupported in the latter for movement from a cocked positioninto a flringzposition, spring means'operativelycon-f4 nected to saidhammer for biasingtheilatten-into e said liring position, a sear blockmounted on said receiver for pivotal movement about a transverse axistoward and away from said receiver, a sear plate disposed contiguous tosaid sear block and mounted on the latter for Sliding movementlongitudinally thereof and for pivotal movement about a secondtransverse axis spaced from said rst transverse axis, said sear platehaving its upper end extending through said receiver and engageable withsaid hammer in a select position of its sliding and rotary movement forlocking said hammer in said cocked position, trigger means operativelyconnected to said sear block for rotating the latter about said firsttransverse axis and for simultaneously elfecting the sliding and pivotalmovement of said sear plate out of said select position, and reslientmeans operatively connected to said sear plate for biasing the latterinto said select position.

5. In a firearm, a receiver, a hammer disposed within said receiver andslidably supported in the latter for movement from a cocked positioninto a firing position, spring means operatively connected to saidhammer for biasing the latter into said firing position, a sear blockmounted on said receiver for pivotal movement about a transverse axistoward and away from said receiver, a sear plate disposed contiguous tosaid sear block and mounted on the latter for sliding movementlongitudinally thereof and for pivotal movement about a secondtransverse axis spaced from said first transverse axis, said sear platehaving its upper end extending through said receiver and engageable withsaid hammer in a selectposition of its sliding and rotary movement forlooking said hammer in said cocked position, trigger means operativelyconnected to said sear block for rotating the latter about said firsttransverse axis and for simultaneously electing the sliding and pivotalmovement of said sear plate out of said select position, and resilientmeans opera-A tively connected to said sear block for biasing the latteraway from said receiver.

6. In a firearm, a receiver, a hammer disposed within said receiver andslidably supported in the latter for movement from a cocked positioninto a firing position, spring means operatively connected to saidhammer for biasing the latter into said firing position, a sear blockmounted on said receiver for pivotal movement about a transverse axistoward and away from said receiver, a sear plate disposed contiguous tosaid sear block and mounted on the latter for sliding movementlongitudinally thereof and for pivotal movement about a secondtransverse axis spaced from said first transverse axis, said sear platehaving its upper end extending through said receiver and engageable withsaid hammer in a select position of its sliding and rotary movement forlocking said hammer in said cocked position, trigger means operativelyconnected to said sear block for rotating the latter about said rsttransverse axis and for simultaneously effecting the sliding and pivotalmovement of said sear plate out of said select position, resilient meansoperatively connected to said sear plate for biasing the latter intosaid select position, and another resilient means operatively connectedto said sear block for biasing the latter away from said receiver.

EDGAR D. MARTIN. GEORGE E. MARTIN.

REFERENCES CITED The following references are of record in the le ofthis patent:

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